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Qualitative Fit Test
A qualitative fit test relies on the worker’s ability to detect the presence of a certain substance through taste or smell through their respirator. Accepted test agents include isoamyl acetate (banana smell) for use with organic vapor cartridges, and a saccharin fit test (sweet taste) or a Bixtrex fit test (bitter taste) for use with particulate filters of any class. If the wearer has not detected the solution after a series of movements, breathing, and talking, the respirator fit passes the test.
Quantitative Fit Test
A quantitative fit test uses a machine to detect the numeral amount of leakage into the respirator. A hose will attach the machine to a probe on the face piece. A PortaCount Pro is an ambient particle counting device used in quantitative fit testing to produce Fit Factor results – a measure of how well-sealed a respirator is to the wearer’s face. This is expressed as a ratio, for example, a fit factor of 100
means that the filtered air inside of the respirator is 100 times cleaner than the air outside of the respirator. In terms of the particle size range that the PortaCount Pro can measure, the 50% cut off is 0.02 micrometres (µm), meaning half of the 0.02 particles will be counted and half will not be. Up to 100% of the particles at the size of 0.04 µm will be counted.
A PortaCount Pro can be used with a PAPR so long as the mask is in negative-pressure mode. It is also important to note that no smoking is permitted within 60 minutes before a fit test as exhaled particles from the smoke will be counted and a lower fit factor will be recorded.
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